Heater activating apparatus with a switchable current controlling element

Abstract

A heater activating apparatus includes a power source, a heater heated to which is applied to voltage from the power source, and a current regulating element. The voltage from the power source is applied to the heater through the current regulating element when the heater is initially to energized, and thereafter, the voltage is applied to the heater without passing through the current regulating element.

What is claimed is: 
     
       1. A heater activating apparatus comprising: a power source;   a heater for generating heat by application of a voltage provided from said power source and causing a current to flow therethrough;   a current regulating element; and   a timer driven by a driving signal for said heater;   wherein the voltage from said power source is applied to said heater through said current regulating element only when said heater is initially energized, and thereafter changed over such that the voltage is applied to said heater without passing through said current regulating element, such change-over being effected after a predetermined time period determined by said timer.   
     
     
       2. A heater activating apparatus according to claim 1, further comprising a first circuit for applying the voltage from said power source to said heater through said current regulating element; a second circuit for applying the voltage from said power source to said heater without through said current regulating element; and selection means for selecting the energization of said heater by said first circuit and the energization of said heater by said second circuit. 
     
     
       3. A heater activating apparatus according to claim 1, wherein said heater is turned ON or OFF to maintain a heating element at a predetermined temperature. 
     
     
       4. A heater activating apparatus according to claim 3, wherein said heater is a heater adapted to heat said heating element for fixing a toner image onto a recording medium by heat. 
     
     
       5. A heater activating apparatus according to claim 1, wherein said heater comprises a halogen heater. 
     
     
       6. A heater activating apparatus, comprising: a power source;   a heater heated by application of a voltage from said power source and causing a current to flow therethrough;   a power thermistor; and   a timer driven by a driving signal for said heater,   wherein the voltage from said power source is applied to said heater through said power thermistor element only when said heater is initially energized, and, after a predetermined time period determined by said timer, the voltage is applied to said heater without passing through said power thermistor.   
     
     
       7. A heater activating apparatus according to claim 6, further comprising: a first circuit for applying the voltage from said power source to said heater through said power thermistor;   a second circuit for applying the voltage from said power source to said heater without passing through said power thermistor; and   selection means for selecting the energization of said heater by said first circuit and the energization of said heater by said second circuit.   
     
     
       8. A heater activating apparatus according to claim 6, wherein said heater comprises a heating element, wherein said heater is turned ON and OFF to maintain said heating element at a predetermined temperature. 
     
     
       9. A heater activating apparatus according to claim 9, wherein said heater is a heater adapted to a heat said heating element for fixing a toner image onto a recording medium by heat. 
     
     
       10. A heater activating apparatus according to claim 6, wherein said heater comprises a halogen heater. 
     
     
       11. A heater activating apparatus, comprising: an AC power source;   a heater generating heat by application of AC voltage from said AC power source;   a current regulating element;   selection means for selecting a first transmission path for applying an AC voltage from said AC power source to said heater through said current regulating element, or a second transmission path for applying the AC voltage without passing through said current regulating element; and   a timer driven by a driving signal for said heater, and the energization of aid heater through said current regulating element is changed over by said selection means to the energization of said heater without passing through said current regulating element, after a predetermined timer period determined by said timer.   
     
     
       12. A heater activating apparatus according to claim 11, wherein said selection means has an interruption member for interrupting current to said current regulating element. 
     
     
       13. A heater activating apparatus according to claim 12, wherein said interruption member comprises a triac. 
     
     
       14. A heater activating apparatus according to claim 11, wherein said current regulating element comprises a power thermistor. 
     
     
       15. A heat activating apparatus according to claim 11, wherein said heater comprises a heating element, and wherein said heater is turned ON and OFF to maintain a heating element at a predetermined temperature. 
     
     
       16. A heat activating apparatus according to claim 15, wherein said heater is a heater adapted to heat said heating element for fixing a toner image onto a recording medium by heat. 
     
     
       17. A heat activating apparatus according to claim 11, wherein said heater comprises a halogen heater. 
     
     
       18. A temperature control apparatus, comprising: an AC power source;   a heater for generating heat by application of an AC voltage from said AC power source;   a heat member to be heated by said heater;   a temperature detection member for detecting a temperature of said heat member; and   power supply control means for ON-OFF controlling said AC power source in accordance with the detected temperature so that the detected temperature of said temperature detection member is maintained at a set temperature, said power supply control means having a first transmission path for applying the power from said AC voltage source through a current regulating element, and a second transmission path for applying the power from said AC voltage source without passing through said current regulating element,   wherein after the power is supplied through said first transmission path, the power source is switched to said second transmission path every time said power supply control is in the ON state.   
     
     
       19. A temperature control apparatus according to claim 18, wherein said AC power source has a interruption member for interrupting the current to said current regulating element. 
     
     
       20. A temperature control means according to claim 19, wherein said interruption member is a triac. 
     
     
       21. A temperature control apparatus according to claim 18, further comprising a timer driven by a driving signal for said heater, and changing means for changing said AC power source by said first transmission path to said second transmission path after a lapse of a predetermined time period determined by said timer. 
     
     
       22. A temperature control apparatus according to claim 18, wherein said current regulating element is a power thermistor. 
     
     
       23. A temperature control apparatus according to claim 18, wherein said heater is a heater adapted to heat said heating element for thermally fixing a toner image onto a recording medium by heat. 
     
     
       24. A temperature control apparatus according to claim 18, wherein said heater is a halogen heater.